Concrete roof and wall structure



Nov. 20, 1962 A. c. AVRIL 3,064,392

' CONCRETE ROOF AND WALL STRUCTURE Filed Sept. 22, 1953 GSheets-Sheet 1IN V EN TOR.

' ATTORNEYS.

Nov. 20, 1962 A. c. AVRIL CONCRETE ROOF AND WALL STRUCTURE 6Sheets-Sheet 2 Filed Sept. 22, 1955 ATToeA/gs.

Nov. 20, 1962 A. c. AVRIL CONCRETE ROOF AND WALL STRUCTURE 6Sheets-Sheet 3 Filed Sept. 22, 1953 ATTORNEYS Nov. 20, 1962 A. c. AVRIL3,064,392

CONCRETE ROOF AND WAL L STRUCTURE Filed Sept. 22, "1953 6 Sheets-Sheet 4e0 J g/ Mfi. BY

ATTORNEYS 1962 A. c. AVRIL 3,064,392

CONCRETE ROOF AND WALL STRUCTURE Filed Sept. 22, 1953 GSheets-Sheet 5 umum mm s. 8N I! O3 m mm mm w m mmJ I i J on & .4 mw vm m m rm m h Mk M.BY m zwn 5 5 mm Ndv. 20, 1962 A. c. AVRIL CONCRETE ROOF AND WALLSTRUCTURE 6 Sheets-Sheet 6 Filed Sept. 22, 1955 Ll Q INVENTOR BY 105ml,i

ATTORNEYS 3,064,392 CONCRETE RGQF AND WALL STRUCTURE Arthur C. Avrii,Wyoming, {)hio, assignor to A and T Development Qorporation, St.Bernard, Shin, a corporation of ()hio Filed Sept. 22, 1953, Ser. No.381,589 2 (Ilaims. (Cl. 59-147) This invention relates to theconstruction of concrete buildings and is directed in particular to aconcrete roof structure for erection upon the walls of such buildings.The invention involves both method and apparatus aspects, both relatingto the construction of a monolithic roof slab and the construction of aceiling which is spaced downwardly relative to the roof slab for heatinsulating purposes.

The present application is a continuation in part of the copendingapplication of Arthur C. Avril entitled Methd and Apparatus For ErectingConcrete Structures, Serial No. 85,748 which was filed on April 6, 1949now abandoned.

The method of the copending application involves the erection ofconcrete building walls by pouring successive horizontal courses of wetconcrete without the use of conventional wooden forms. For this purpose,precast concrete columns are erected in perpendicular position upon afooting and in spaced relationship to one another. The vertical columnsdelineate the plane and thickness of the wall and serve as guides forhorizontal courses of narrow metal forms which are clamped againstopposite sides of the adjacent columns. In this position, the formsprovide shallow troughs extending lengthwise between the columns. Uponthe installation of each set of forms, wet concrete is poured andtarnped into the trough which they provide and the procedure of erectingadditional form courses one upon another and of pouring and tamping theconcrete is repeated until the desired wall height is obtained. Thismethod produces a monolithic wall with the precast beams embedded in thewall and also provides a simple inexpensive procedure completelyeliminating the construction of wooden forms.

The metal forms which are utilized in practicing the above method arethe subject matter of another copending application of Arthur C. Avrilentitled Sectional Concrete Forms, Serial No. 277,830, filed on March21, 1952, now Patent No. 2,762,105 and the forms disclosed therein arealso utilized in erecting the roof slab of the present application.

One of the primary objects of the present invention has been to providea monolithic roof slab involving the use of precast concrete beams whichare arranged to perform the double function of supporting a series offorms in a predetermined plane for pouring the slab, and of providingrigid means for anchoring the spaced ceiling structure after the formsare removed from the hardened slab.

By virtue of the precast beams, the forms are erected in a rapidinexpensive manner without the use of conventional forms, since thebeams themselves provide the supporting and guiding means for the forms.After pouring the slab, the beams are partially embedded in it toprovide strength; moreover, the lower edge portions of the beams projectdownwardly from the slab and provide irregular surfaces to which theceiling structure is directly keyed for support.

In erecting the slab, the precast beams, which are generally of I-beamshape in cross section, are placed across the walls of the buildingspanning the walls at a spacing related to the length of the metalforms, such that the forms may be placed transversely between adjacentbeams and supported by the beams. Accordingly, the beams delineate theplane of the roof and simplify the erection procedure since the usualexpensive form Work is elimi- Patented Nov. 20, 1962 nated completely.Otherwise expressed, the beams themselves form an essential part of theform work; however it is a rather simple matter to adjust themindividually to a common plane to form the roof skeleton. Thereafter theforms are placed on them in a routine manner and the slab is poured to apredetermined depth across the forms with the marginal portion of theslab resting upon the top of the walls. This bonds the slab both to thebeams and to the walls to provide a monolithic concrete structure.

In order to support the forms, pairs of rails, preferably of wood, areplaced against the web of each beam on opposite sides, with the railsresting upon the lower flange of the beam and clamped temporarily byC-clamps against the opposite sides of the web. The rails projectoutwardly on opposite sides beyond the edges of the flanges and providesupporting surfaces for the opposite ends of the forms which are placedcrosswise between adjacent roof beams. The forms are slightly shorterthan the spacing between the lower flanges of adjacent beams;consequently, upon removal of the C-clamps and rails, the forms may bedropped from between the beams.

The upper surfaces of the rails collectively are disposed in a plane tolocate the forms below the upper flanges of the beams such that theflanges above the forms are embedded in the roof slab. After theconcrete slab has been poured and allowed to set, the C-clamps and railsare readily detached from the beams, allowing the forms to be droppeddownwardly from the slab surface.

As noted above, the upper flanges of the roof beams are embedded in theslab, leaving their lower flanged portions projecting downwardly belowit. The ceiling is anchored upon a framework preferably of wood, whichderives support directly from the lower flanges of the roof beams. Forthis purpose,'the ceiling structure includes wooden stringers extendingtransversely between adjacent beams with their opposite endsconfigurated to key into the sides of the roof beams above the lowerflanges, thus anchoring the stringers firmly to the beams. Verticalstuds are attached to the wooden stringers, the studs having upper endsengaged against the surface of the roof slab; thus the stringers areheld rigidly by the beams and slab against deflection in the verticalplane. Thereafter, furring strips, which extend at right angles to thestringers, are attached to the lower end portions of the studs whichproject downwardly below the stringers. The furring strips thus securethe stringers rigidly in their transverse relationship to the beams andalso provide means for attaching the ceiling which may be either of lathand plaster or of dry wall construction.

From the foregoing, it will be observed that in addition to reinforcingthe roof slab, the roof beams, which are easily set and adjusted todelineate the roof plane or planes, are utilized both for supporting andguiding the forms and for providing a direct anchorage for the ceilingstructure. By taking advantage of the I-beam cross section of the beamarrangement therefore, the roof and ceiling is improved structurally andthe construction costs are reduced.

A further object of the invention has been to provide means for directlyattaching a spaced wall panel to the concrete walls to provide a deadair space extending downwardly from the ceiling. During erection of thewalls, sheet metal form ties are utilized to space and attach the wallforms relative to one another. These spacers are left embedded in theconcrete wall and, after removal of the forms, provide limbs whichproject from the inner surface of the wall. The projecting limbs, whichare ductile, are utilized to attach wood furring strips to the innersurface of the wall, the limbs being clinched over upon the strips toclamp the strips firmly against the concrete wall. Thereafter, metallath may be nailed directly to the furring strips for application of aplastered wall or wall board panels or plywood may be attached in theusual manner.

Various other features and advantages of the invention will be morefully apparent to those skilled in the art from the followingdescription, taken in conjunction with the drawings.

In the drawings:

FIGURE 1 is a top plan view of a building, showing the roof beams for ahat roof installed and the forms and reinforcing rods in position at oneportion of the building ready for pouring the slab.

FIGURE 2 is a view similar to FIGURE 1, showing the concrete roof slabpartially poured, with the remaining forms set in position.

FIGURE 3 is a sectional view taken on line 3-3 FIG- URE 2 illustrating apart of the roof slab and temporary supporting structure for the forms.

FIGURE 4 is a sectional view taken on line 44 FIG- URE 3, illustratnigparticularly the attachment of the temporary rails to the roof beams andsupporting the ends of the forms.

FIGURE 5 is a plan view of one of the end panels of the wall forms whichare utilized in pouring the roof.

FIGURE 6 is an end view of the form panel illustrated in FIGURE 5.

FIGURE 7 is a perspective view illustrating the flat roof of FIGURES land 2 at completion.

FIGURE 8 is a sectional view showing the roof beams erected to provide apitched roof.

FIGURE 9 is an enlarged view similar to FIGURE 8, showing the formsinstalled and the slab partially poured.

FIGURE 10 is a sectional View taken on line 1010 FIGURE 9, detailing themounting of the forms similar to FIGURE 4.

FIGURE 11 is a sectional view similar to FIGURE 10, showing thecompleted roof slab with'the forms removed, illustrating the attachmentof the ceiling framework to the precast beams.

FIGURE 12 is a sectional view taken on line 1212 FIGURE 11, furtherdetailing the ceiling structure.

FIGURE 13 is a sectional view taken on line 1313 FIGURE 12, furtherillustrating the ceiling structure;

FIGURE 14 is a plan view illustrating one of the form ties which areutilized in clamping the wall forms to the columns during erection ofthe walls and which are later utilized in clinching the furring stripsfor the wall lath or panel as illustrated in FIGURE 12.

The fiat roof structure illustrated in FIGURES 1 to 4 and 7 is similarto that disclosed in the copending application and the pitched roof ofFIGURESS to 13 follows the same principles of construction. In bothforms, the roof slab comprises a reinforced concrete structure which iserected by initially locating across the top of the building walls,series of precast concrete roof beams or purlins spaced from one anotherand spanning the walls. Thereafter, the sheet metal forms are mountedtransversely between adjoining roof beams in side-by-side relationship,with their opposite ends supported by the beams as explained in detaillater. Reinforcing rods are then placed upon the collective forms, thewet concrete is poured, levelled and allowed to set; thereafter theforms are removed from beneath the slab.

, The sheet metal forms impress into the lower surface of the roof slaba geometric arrangement of ribs extending transversely between the roofbeams and imparting a finished architectural ceiling pattern. Dependingupon the utility and architectural design of the building, this patternmay be left exposed, or on the other hand, a plastered or dry wallceiling may be installed in spaced relationship to the surface patternto provide a dead air space for heat insulation. 7

It will be understood at this point, that the roof slab and its precastconcrete beams form a monolithic concrete structure bonded to thewallsand possessing a high degree of mechanical strength and that thestructure is essentially the same whether the roof is flat or of thepitched variety.

As disclosed in the drawings, the present roof structure is constructedupon concrete building walls erected by the method disclosed in thecopending application. According to the prior application, precastvertical columns are first installed and the walls are erected bypouring courses of wet concrete successively one upon another, utilizingsectional forms which are clamped in pairs against the opposite sides ofvertical precast columns. The columns are erected at spaced pointsaccording to the plan of the building and in true vertical positions;thus they serve as guides during the erection of the forms so as toeliminate expensive wooden form work and simplify the erectionprocedure. As the wet concrete is poured into the courses of forms andtamped, the successive courses bond firmly to one another and to thecolumns and embed the columns in the wall as an integral part of it.

When the full height of the complete building wall is obtained, socketsare formed in the upper portions of op posed walls to receive theopposite ends of the precast roof beams. The beams span the walls andare adjusted to a common horizontal plane in the case of a flat roof orthey are adjusted to the desired angle in the case of a pitched roof;thereafter, the form panels are installed lengthwise between the roofbeams. To simplify the setting of the forms, the roof beams are locatedupon centers suitable to receive between them the elongated forms(FIGURE 5) which were previously used in constructing the wall. It willbe understood that placing the beams accurately upon the wallsdetermines the plane of the roof slab in advance and after the beams areaccurately located, the forms may be set rapidly by unskilled workmenand without utilizing complex wooden form structures.

Briefly, the present structure and method of erection takes advantage ofthe I-beam cross section of the beams to provide the followingsignificant improvement over conventional building practices:

In the first place, the prelocated roof beams simplify the erection ofthe concrete forms since the forms are readily set in positiontransversely spanning adjacent beams and supported by wood railstemporarily clamped,

on opposite sides of the beams, as shown in FIGURES 3 and 4. The beamsthemselves thus directly receive and support the forms and weight loadof the concrete roof slab without intricate form construction.

Secondly, after the roof slab is set and the forms removed from it, theroof beams are utilized to support the ceiling frame, again takingadvantage of their I-beam cross section, as shown in FIGURES 11 and 12.For this purpose, a series of ceiling joists or stringers, preferably ofwood, are wedged between adjacent roof beams,-

the opposite ends of the joists being shaped to mate with the I-beamcross section such that the joists are keyed rigidly to the beams. Theceiling proper is supported by a suitable wood frame attached to thejoists as explained later in detail.

Referring to FIGURE 2, which illustrates in plan view the erected walls15 of the building and the erection of the forms thereon for a flat roofstructure, it will be observed that the precast roof beams 16 arelocated in sockets 17 formed in the upper portion of the walls onoppdsite sides. The concrete beams art somewhat thicker than thevertical columns previously noted and'the sockets have sufiicient depthto locate the upper edges of the beams flush with the top of the wall.The beams are spaced apart to receive between them the forms 18, withthe end portions of the forms located downwardly of the flanges 20 ofthe beams as indiciated in FIGURE 4.

As disclosed in the copending application, the forms used in the wallconstruction are of a length adapted to the present day modularconstruction system and are extensible lengthwise. They are made up ofthree sections, consisting of an intermediate section and a pair of endsections telescopically related. The individual sections preferably havea length corresponding to the eight foot lineal unit or multiple thereofused in locating I-beams and columns, such that the sections fit betweenthem. In the present disclosure, the end form sections are utilized inpouring the concrete roof and the precast roof rafters are placed ateight foot centers adapting the form sections to fit endwisely betweenthe beams.

As best shown in FIGURE 4, the ends of the first row of forms 18 extendfrom the inside surface of the wall and their ends adjacent the wall aresupported by a horizontal wood beam 21, which rests upon verticalshoring members 22. The opposite ends of the first and succeedingcourses of forms are supported by rails 23* 23, for example, wood two byfours, which seat against opposite sides of the web 24 of the roof beam16, with their lower edges resting against the lower flange 25 of thebeam on opposite sides. The two by fours are clamped against theopposite sides of the web by C-clamps 26 which are spaced from oneanother along the beam as shown in FIGURE 3. The wood rails 23 extendoutwardly beyond the side edges of the flange 25 to support the ends ofthe flanges; thus, upon removal of the rails, the forms can be droppeddown from between the adjacent roof beams without difficulty.

As best shown in FIGURE 3, the walls of the building are provided withvertical reinforcing rods 27 which project upwardly beyond the top ofthe wall. After the forms are mounted, the extended ends 28 of thereinforcing rod are bent over upon the forms, such that upon pouring theedges of the roof slab are tied to the walls. In addition, longitudinaland transverse reinforcing rods 39 and 31 (FIGURE 1) are installed uponthe forms to strengthen the roof slab. These rods have their endsextended to the walls around the periphery of the building with theirends interposed between the extended ends 23 of the wall reinforcingrods.

It will be observed in FIGURES 3 and 4, that the wet concrete roof slabis bonded to the upper portion of the concrete roof beams and to theupper edges of the walls so as to provide a monolithic concrete roof andwall structure.

To prevent sagging of the relatively flexible sheet metal forms underthe weight load of the wet concerte, the forms derive supplementalintermediate support from the temporary scaffolding indicated generallyat 32 in FIG- URES 3 and 4. The scaffolding may be a commercial product,for example, tubular framework having vertical adjustment means (notshown) so as to brace the forms at points in a common plane. Thescaffold structure rests upon the floor slab of the building andincludes vertical columns 33 suitably braced as at 34. The columns haveat their upper ends respective horizontal cross members 35 attached tothe vertical columns and reinforced by the bracing members 34. The formsare engaged by respective wood beams 36 resting upon the cross members35 and extending at right angles across the lower edges of the forms.The beam 36 engages the intermediate portions of the forms as shown inFIGURE 4 and maintains all of the forms in a common horizontal plane toprevent any tendency to spring or sag when the wet concrete is pouredinto them.

It will be understood that the roof beams and their wood rails 23provide the primary support for the forms and also, by locating themaccurately in a common plane relative to one another, delineate theplane or planes of the roof slab. The scaffolding provides added supportfor the forms and the wet concrete slab. Moreover, being verticallyadjustable, the scaffolding promotes safety and convenience in removingthe forms since it may be lowered just enough to drop the forms from thehardened slab for convenient removal.

As best shown in FIGURES 1, 2 and 3, a rail 37 preferably formed ofwood, forms a curbing or closure to retain the wet concrete which ispoured to a level above the plane of the forms and above the top of thebuilding Wall. The rail 37 extends around the periphery of the buildingas indicated in FIGURE 1 and forms a permanent part of the roofstructure. The rails 37 are held in place temporarily by wires 38, eachhaving an end anchored upon the end extensions of the form ties 46 whichare left projecting from the wall after the wall forms are removed asexplained later. The wires extend over the side and top of the rail 37and are attached as at 41 to the bent ends 28 of the wall reinforcingthe rods. Rail 37 is anchored permanently to the roof slab by studs orlag screws 42 (FIGURE 4) passing into the rail and having an outer endportion embedded in the roof slab.

After the forms are installed and braced by the scaffolding, and thereinforcing rods 30 and 31 properly positioned and wired together, thewet concrete is poured into the forms as indicated at 43 in FIGURES 2and 3. The wet concrete is distributed uniformly and, by means oflevelling boards, is worked level and flush with the curb rails 37 in amanner well known in the building trade. After the slab has setthoroughly, the scaffolding 32 is adjusted downwardly a sufiicientdistance to allow the forms to be dropped from the slab. The C-clampsare then loosened and the rails 2323 removed so that the forms can 'bereleased and dropped upon the top of the scafiolding. Thereafter, theforms can be removed in a safe and convenient manner from thescaffolding.

The form contour provides a ribbed ceiling having a finishedarchitectural surface with the upper portions of the roof beams bondedin the slab and the lower portions of the beams projecting downwardlybelow the plane of the slab to serve as support means for the ceilingstructure as explained in detail later. The exposed slab may be utilizedin this condition as the ceiling if desired, or the downwardly spacedplastered or dry wall ceiling may be installed beneath the slab for heatinsulation.

Referring to FIGURES l1 and 12, the spaced ceiling, indicated generallyat 44, is shown installed on a pitched roof building, however it will beunderstood that the identical construction is applied to the flat roofshown in FIGURES 3 and 4. The ceiling is supported by a framework,preferably of wood, indicated generally at 45 which derives its supportdirectly from concrete roof beams in a manner generally similar to theforms previously described. As shown in FIGURE 11, the ceiling framestructure is supported by a series of ceiling joists or stringers 46which extend transversely between the spaced beams, with the oppositeends of the stringers wedged between adjacent beams and rigidlysupported by the lower fiange 25 thereof.

For this purpose, the opposite ends of the stringers are cut to interfitthe l-beam cross section of the beams, the upper portion of eachstringer having a projecting tongue 46a which overlies the flange 25 andabuts the web 24 of the beam. The stringers are installed by placingthem in a generally diagonal position between adjacent beams, thenforcing them to right angular relationship, whereby the stringers arefirmly wedged between the beams. The stringers are then rigidly fixed ina common plane by attaching to the sides of the stringers a series ofvertical studs 47, the studs having upper ends which seat upon the lowersurface of the concrete slab; therefore, the stringers and theirassociated parts are locked securely against deflection in a commonplane. The ends of the stringers which abut the walls of the buildinghave their ends configurated to nest between the ribs of the Walls,which have a surface pattern corresponding to the lower surface of theroof slab.

Attached to the lower ends of the vertical studs is a series of furringstrips 48 which extend parallel to the roof beams and transverse to thestringers. The furring strips thus tie the stringers securely relativeto one another in right angular wedging engagement with the roof meansand also support the ceiling itself. In the construction shown inFIGURES l1 to 13, metal lath 50 is attached to the furring strips in theusual manner and the metal lath is plastered as at 51. In dry wallconstruction, the lath and plaster is omitted and instead, conventionalplasterboards or plywood panels (not shown) are attached directly to thefurring strips in place of the lath and plaster.

It will be understood that the several parts of the wood framework 45are preferably nailed together, the stringers first being wedged inbetween the concrete beams and walls and the vertical studs and furringstrips thereafter nailed to them. This structure provides a rigidsupport for the downwardly spaced ceiling and provides an ample dead airspace beneath the roof slab for thermal insulation.

It will be apparent from the foregoing disclosure, that the roof beamsreinforce the roof slab and are also utilized for the purpose ofsupporting and guiding the forms in a common plane and for providing arigid support for the spaced ceiling structure. In their function asform supports, the prelocated beams allow the forms to be set in asimple manner by unskilled workmen. In their function as anchorage meansfor the ceiling structure, the beams collectively provide a simple modeof attaching the spaced ceiling structure to the concrete ceiling slab.

According to the pitched roof structure shown in FIG- URE 8, the roofbeams 16 are joined at center by bolts '52 passing through metalclamping plates 5353 which areseated against the webs of the beams onopposite sides. The lower ends of the beams are joined by means of bolts54 to respective cross beams 55 which are seated in sockets 17 formed inthe top portion of the Walls as described earlier. The cross beams spanthe building Walls and, by their connection to the lower ends of theroof beams, provide a self-sustaining truss suitable to resist thelateral forces developed by the weight load of the roof.

'If a fiat ceiling is desired, it may be attached to the cross beams 55,otherwise the ceiling structure is tied to the pitched beams asdescribed earlier. Asindicated by the broken lines a in FIGURE 9, thebuilding may a simple manner by unskilled workmen. In their funccrossbeams 55 are omitted and the upper ends of the roof beams rest directlyupon the bearing Wall.

The forms are installed between the pitched roof beams as shown inFIGURES 9 and 10 in identically the same manner as the flat roofinstallation' It will be noted that the ends of the forms are supportedby rails 23-23 and C-clamps 26, and that the forms are bracedintermediately' by the scaflolded sections 32. In this instance thescaflolds are adjusted to several elevations to accommodate the woodbeams 36 which are located at several planes corresponding to theincline of the roof beams.

It will be observed in FIGURE 9, that the collective forms extendingacross the inclined roof beams present a series of troughs 56 extendinghorizontally along the inclined roof skeleton. The troughs form the ribs57 in the ceiling and are effective to key the wet concrete slab to theinclined form surface. roof has a steep pitch, the troughs aidinovercoming the tendency of the wet concrete to slide down the inclinedform surface.

Referring to FIGURES 5 and 6; each form 18 comprises a panel 58including marginal flanges 60 bent at right angles to the plane of theform. The flanges provide stiffness and also provide interfaces betweenadjoining forms. The central portion 61 of panel 58 is depressed withrespect to theplane of the form on the side opposite the flanges (FIGURE6) to further stiffen the form. This panel impresses the depressed panel62 in the surface of the ceiling (FIGURE 12). The flat marginal portions63-63 intermediate the flanges and depressed panel collectively impressthe ribs 57 in the ceiling surface. In addition, the opposite endportions of the form include flat end panels 6L -64 which provide theribs 65 In the event that the adjoining the roof beam on opposite sides(FIGURE ll). The ribs 57 provide maximum strength while keeping the deadweight as low as possible; The ribs alongside the roof beams extend atright angles to the ribs 57 and thus strengthen the slab along the axesof the beams.

As best shown in FIGURE 12 the interior wall surface is molded by thesame forms as are utilized in pour ing the roof slab, thereforethe'interior surface of the wallshave a geometric pattern impressionmatching ceiling surface. In erecting the walls, the form ties 40 areplaced crosswise of the inner and outer forms and are utilized to clampthe forms in spaced relationship against the vertical columns. Asindicated in FIGURE 14, the outer ends of the form ties 46 are split toprovide a pair of limbs, 6767 which are clinchedrespectively in oppositedirections upon the opposite sides of the form flanges as described inthe copending application. After the wall hardens, the limbs arestraightened out for removal of the forms, the ties being embedded inthe concrete wall. broken off flush with the outside surface of theWall.

In the event that it is desirable to take advantage of the ribbedprofile of the wall to form a dead air space for heat insulation similarto the ceiling structure, the

limbs of the form ties are utilized to mount the furring' strips for thewall panel structure. As shown in FIGURE 12, pairs of furring strips'68, preferably of wood, are attached horizontally to the concrete wallsurface, with the furring strips located above and below the protrudinglimbs. The strips are attached by' clinching one of the limbs upwardlyover the opposite strip as indicated at 70 and by clinching the otherlimb downwardly over the lower strip as indicated at 71. The respectivepairs of strips are thus attached rigidly at spaced intervals to theWall surface for attachment of metal plaster lath or wall panels. Asshown in FIGURE 12, plaster lath indicated at 72 is nailed directly tothe strips in the conventional fashion and thereafter a coating of wallplaster is applied. By virtue of the furring strips and cavities in thewall surface, a series of dead air cells, indicated at 73, is formedbetween the concrete and plaster walls.

From the foregoing, it will be noted that the forms:

are supported in side-by-side relationship upon the roof beamswithout'being tied together, thus simplifying the.

setting operation. By virtue of the longitudinal flanges of the forms,interfaces are provided between them such that all parts of the slab arein direct contact with the metal form surfaces to impress a finishedarchitectural surface texture to the slab.

The ribbed pattern of the slab surface providesmaximum strength bothalong the axes of the beams and transversely to them and thereby reducesthe weight load of the slab while providing adequate strength. Thisallowsthe beams to be set a great deal further apart than inconventional structures, the beams of the present disclosure beinglocated at eight foot centers as dictated by the length of the forms.

Having described my invention I claim:

1. A concrete roof slab and ceiling structure for installation upon thewalls of a building comprising, a plurality of precast concrete roofbeams each havingintegral upper and lower flanges joined by a verticalweb,

said integral lower flanges projecting along opposite sides 7 of said.web, said roof beams laterally spanning spaced support members of thebuilding and disposed in spaced parallelism relative to one another, aconcrete roof slab having marginal edges overlying the building supportmembers, the slab extending across said roof beams with the upperflanges of the roof beams embedded therein and providing a monolithicstructure, the web and lower flanges of the roof beams projectingdownwardly to a common plane spaced from the lower surface of theconcrete slab, a plurality of stringers extending transversely be- Vtween adjacent roof beams and disposed in spaced paral lelism relativeto one another, the stringers having a length The protruding ends of thelimbs are then' corresponding to the spacing of the adjacent roof beams,the opposite ends of said stringers having a configuration mating withthe webs and lower flanges of adjacent roof beams and keying thestringers between adjacent roof beams, a series of vertical studsattached to the stringers, the studs having upper ends engaged againstthe lower surface of the concrete slab and locking the stringersdownwardly against the lower flanges of the roof beams, said studshaving lower ends projecting downwardly below the stringers, a pluralityof furring strips extending transversely across said stringers andattached to the lower ends of the vertical studs, said furring stripslocking the stringers transversely in keyed position between the roofbeams, and a ceiling panel attached to the lower surface of said furringstrips and disposed in spaced relationship to the roof slab.

2. A concrete roof slab and ceiling structure for installation upon thewalls of a concrete building comprising, a plurality of precast concreteroof beams each having an irregular surface profile along opposite sidescoextensive longitudinally therewith, said roof beams extending acrossthe walls of the building and disposed in spaced parallelism relative toone another, a concrete roof slab having marginal edges overlying thebuilding walls and bonded thereto, the slab extending across said roofbeams, the lower surface of the roof slab having respective longitudinalribs projecting downwardly therefrom, said longitudinal ribs overlyingsaid roof beams and co-extensive therewith, the upper edge portions ofthe roof beams embedded in said longitudinal ribs and providing amonolithic structure, the lower portions of each roof beam projectingdownwardly to a common plane spaced from the lower surface of theconcrete slab, a plurality of stringers extending transversely betweenadjacent roof beams and disposed in spaced parallelism relative to oneanother, the stringers having a length corresponding to the spacing ofthe adjacent roof beams, the opposite ends of each of said stringershaving a configuration mating with the irregular surface profiles ofadjacent roof beams and keying the stringers between adjacent beams, aseries of vertical studs attached to the stringers, the studs havingupper ends engaged against the lower surface of the concrete slab andlocking the stringers downwardly with respect to the roof beams, saidstuds having lower ends projecting downwardly below the stringers, aplurality of furring strips extending transversely across said stringersand attached to the lower ends of the vertical studs, said furringstrips locking the stringers transversely in keyed position between theroof beams, and a ceiling panel attached to the lower surface of saidfurring strips and disposed in spaced relationship to the roof slab.

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